Selections Allow: Maximum number of create a class slots shown (is not affected by Preset Classes).

Preset Classes: Global = Both teams use these classes, Per-Team each team has their own classes

Once your classes have been set return to Custom Games main menu.

Open console and enter the command: \gamesettings_generateconfig

The game will hitch for a moment but now we can exit out of the game.

Go to your Black Ops III root directory and open the folder local_storage.

Find the most recent created .cfg file (usually it's the one ending in _v55 but that can be changed) and open it.

Inside you'll see what makes the game set all the classes for you and various other modified settings from the Custom Games screen.

What we need to do right now is cut out the second column: gametypesettingsuse Notepad++ to remove it all for you or use Search & Replace in your text editor.

Now our lines should be similar to this: gametype_setting cacloadouts 0 customclass 0 primaryattachment1 0

Copy the entirety of the config to your own mp_mod.cfg (if you don't have this file create it in the root of your mod).

Now launch the game and make sure to load the mod from the Main Menu as of now the config isn't executed from command line/Launcher (this has been fixed by Treyarch and will be included in a later update).